A 2-year-old girl presents with sparse hair, recurrent infections, absent lymph nodes, and absent tonsils. Immunological workup reveals absent T and B cells. Genetic testing identifies an ADA gene mutation. Which treatment offers the possibility of curative therapy?

• A Subcutaneous PEG-ADA enzyme replacement therapy only
• B Monthly IVIG infusions
• C Long-term prophylactic cotrimoxazole only
• D Haematopoietic stem cell transplantation (HSCT) ✓

Explanation

ADA-SCID (adenosine deaminase–severe combined immunodeficiency) is caused by mutations in the ADA gene leading to toxic accumulation of deoxyadenosine in lymphocytes, depleting both T and B cells. HSCT from a matched related donor is the curative treatment of choice. PEG-ADA enzyme replacement is a bridging therapy, not curative. Gene therapy (retroviral or lentiviral vector-based ADA gene transfer) is another curative option now available at specialized centres. IVIG only provides humoral protection; cotrimoxazole only prevents PCP.

Reference: Ghai Essential Pediatrics, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.